New Holland Crow
| New Holland Crow | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
New Holland Crow, Sydney |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Corvus coronoides | ||||||||||||
| Vigors & Horsfield , 1827 |
The New Holland crow ( Corvus coronoides ) is a bird belonging to the genus of ravens and crows ( Corvus ). It occurs exclusively in Australia and some offshore islands. It is the most widespread and best known species of corvids in Australia . New Holland crows utilize a wide variety of food sources and are very adaptable. The IUCN classifies its stock situation as safe ( least concern ).
features
Build and color
Between the sexes of Neuhollandkrähe is neither in the plumage coloration still in Build a dimorphism , the same applies to young and adult birds. It reaches a body length of around 50 cm. The beak is 59.2–63.8 mm long. The New Holland crow has a wing length of 336–373 mm, its tail measures 200–229 mm. The weight is between 506 and 670 g. The front cervical plumage is slightly elongated in them.
The plumage of the New Holland crow is uniformly black. The plumage on the head, neck, top of the body, chest, flanks and the plumage of the upper tail-coverts shine black. The shimmer ranges from a metallic green on the ear covers to a blue-violet shimmer on the other parts of the body. The intensity of the shimmer strongly depends on the incidence of light. The underside of the body including the under tail covers is matt black.
The feathers have a pale gray to medium gray feather base, the feathers are black only from the middle. In living birds, however, the lighter feather base is not visible even in strong winds.
The beak black, the rear third of the upper beak including the nostrils is covered by long bristle feathers. Below the beak is a bare, featherless patch that runs in a V-shape to the chin and the sides of the neck. In adult birds, the iris is whitish with a light blue inner ring. The legs and feet are black.
Fledglings
Young birds are slightly smaller than the adult birds. Their beak is even shorter. The plumage is not as shiny as in the adult. Their beak is still dark gray.
voice
The call of the New Holland crow consists of a long, high-pitched sound that appears plaintive to humans. Calling birds usually sit on a tall tree or a power pole.
Possible confusion
In Australia, come Corvus TYPES society Crow , Tasmankrähe , Salvadorikrähe and Bennett Crow ago that are difficult to distinguish from each other in field observations. However, elongated neck feathers, as are typical of the New Holland crows, are only found in the social crows and the Tasman crows. The most reliable distinguishing feature is reputation.
Distribution area and habitat
Distribution area
The New Holland crow occurs in the eastern half of the Australian continent as well as in the south-west of Australia. It is very rare on the Cape York Peninsula , north of the 16 ° south latitude it has so far only been observed very rarely. In the Atherton Tablelands , which are still part of the tropics, it can only be seen near the coast. In contrast, it is a common and widespread breeding bird in the Australian states of New South Wales and Victoria, which are further north. In South Australia it is absent in the west and northwest, but inhabits the Kangaroo Island , the third largest island in Australia after Tasmania and Melville Island , which is 112 kilometers southwest of Adelaide in the Gulf of Saint Vincent . In West Australia it occurs south of the Nullarbor Plain and mainly inhabits the south and southwest of this state. In contrast, it is rarely seen in the Northern Territory. Most of the observations come from the east and south of this state. In Tasmania, however, the New Holland crow is absent.
Irrgast
The New Holland crow can occasionally be seen as a stray visitor on Lord Howe Island . Observations of a single bird of this species in New Zealand are considered dubious.
Dispersion of the young birds
New Holland crows are generally considered to be very loyal to their location. Adult breeding pairs occupy a territory all year round which has a size of about 120 hectares. Outside of this area they can only be seen very rarely. Young birds stay in the parent bird's territory until they are at least four months old, but typically five months. So far it has not been observed that juveniles have been driven out of the territory by their parents. On the other hand, there seems to be a strong tendency of young birds to join flocks of conspecifics. If they leave the territory of their parent birds, they are initially primarily exposed to aggression from neighboring territory owners.
The squads of young birds, which can contain up to 300 birds. These roam very large areas that can lead them over hundreds of kilometers in search of food. The migratory movements of the troops are mainly determined by the food supply. You can therefore stay in individual regions for a longer period of time. This is more common, especially in the Australian autumn and winter. Smaller troops, on the other hand, tend to remain in an area of around 260 square kilometers.
habitat
New Holland crows are very adaptable and can occupy a wide range of different open habitats. They are usually not found in dense forests. Suitable habitats provide them with sufficient water and either trees or artificial, man-made structures that they can use as nesting and resting places. Due to these comparatively low requirements, they can also be observed more frequently in urban areas.
The typical natural habitats include, above all, forest edges, heaths, scrubland and mangroves, as well as coastal dunes.
General way of life
_1.jpg)
Adult New Holland crows can be observed mostly in pairs, occasionally also in small family groups, if the young birds have not yet left their parents' territory. They can be seen, especially on carrion, occasionally in the vicinity of other bird of prey species such as black kites , wedge-tailed eagles and hawks . The flight is strong and straight, the wing beat varies depending on the prevailing wind strength. On the floor they sway slightly, the body swings a little to the side with every step. New Holland crows, which move faster on the ground, also hop.
Small groups of New Holland crows hate medium-sized to large bird of prey species such as the wedge-tailed eagle, larger kites or harriers , but also herons and spectacled pelicans . They are quickly noticed by their calls and their conspicuous behavior and are shy of people, especially in agricultural land. In contrast, they can become very trusting in urban areas.
food
New Holland crows are omnivores. They mainly eat insects and other invertebrates. But they also cover their food needs with small vertebrates, including small songbirds, their eggs and nestlings, and reptiles. They regularly eat carrion and are therefore often seen along roadsides, where they eat animals that have been killed in traffic. They are also more common in landfills. They find their food mainly on the ground.
New Holland crows occasionally hoard food. A typical situation in which this occurs is on carrion, for example, when the animal is larger than New Holland crows eat at one time. To do this, they carry parts about 100 meters away from the site and bury them in the ground. When a New Holland crow was observed, which found more food in a picnic area than it could eat at one time, the food components were buried in different places and each place was first covered with earth and then with stones and branches.
Reproduction
.jpg)
New Holland crows are not tied to any specific breeding season, nests and clutches can be found in every calendar month. However, they mainly brood in the period from August to November. The nest is usually built in high tree tops. But they also breed on telephone poles and similar man-made constructions. The nest is comparatively large and is made of branches, twigs and roots. The actual nesting trough is covered with bark, grass and remnants of fur or hair. Both parent birds are involved in building the nest. Nest building usually takes two to three weeks. They also use older nests for the next clutch, in which case the nest is usually repaired within five days. Clutches can contain between one and six eggs. However, a clutch size of four or five eggs is typical. The laying interval is one to two days. The female breeds alone, while the male brings food to the nest. The breeding season is just under 20 days. The female herds the nestlings during their first two weeks of life. During this time, too, the male brings food to the nest. Older nestlings are only hovered by the female in bad weather. The nestling period is just under 44 days. Older nestlings that have already flown out while younger siblings are still in the nest often return to the nest when they are being fed. Even after they have left the nest, they are still fed by the parent birds for weeks. About three months after leaving the nest, they are self-employed.
Life expectancy
The mortality rate is highest in immature birds. Of New Holland crows that were ringed in the nest, almost 65 percent did not survive their first year of life. They mostly die in the Australian winter when they are five to six months old. At this point they have broken away from their parent birds and have to cover their nutritional needs independently. The mortality of elderly New Holland crows is a little over 50 percent per annum. H. every second adult New Holland crow will also have its next year of life. The oldest bird to date whose age could be determined from ringing data reached an age of 12 years and five months.
New Holland crow and human
The New Holland crow has long been suspected of killing young lambs. This suspicion, which was based on the fact that they occasionally appear in large numbers near paddocks in which sheep are lambing, has been largely dispelled: They eat dead lambs, miscarriages, but occasionally kill sick or severely weakened lambs. Due to this suspicion, however, they were hunted very heavily by sheep farmers in the past. The use of the New Holland crows in the removal of the carcasses is now increasingly seen. However, they are still causing damage to farms because, among other things, they eat grain provided for the sheep. They also break into the pens with chickens to eat eggs. They can also cause damage in orchards.
Trivia
The to the foliage birds belonging to drop Laubenvogel and spotted bowerbird imitate the calls for several species of birds that know them as predators. This also includes the call of the New Holland crows.
literature
- PJ Higgins, JM Peter and SJ Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . Oxford University Press, Melbourne 2006, ISBN 978-0-195-55884-5 .
Web links
- Videos, photos and sound recordings on Corvus coronoides in the Internet Bird Collection
Individual evidence
- ^ Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 690.
- ↑ Handbook of the Birds of the World on the New Holland Crow , accessed May 7, 2017
- ^ Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 713.
- ↑ a b c Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 691.
- ^ Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 696.
- ^ A b Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 697.
- ↑ a b c d Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 699.
- ^ Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 701.
- ^ Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 709.
- ^ A b Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 710.
- ^ Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 711.
- ^ A b Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 698.
- ^ Higgins, Peter & Cowling: Handbook of Australian, New Zealand & Antarctic Birds: Volume 7 Boatbill to Starlings, Part A: Boatbill to Larks . P. 702.
- ↑ Clifford B. Frith, Dawn. W. Frith: The Bowerbirds - Ptilonorhynchidae . Oxford University Press, Oxford 2004, ISBN 0-19-854844-3 . P. 419.
- ↑ Clifford B. Frith, Dawn. W. Frith: The Bowerbirds - Ptilonorhynchidae . Oxford University Press, Oxford 2004, ISBN 0-19-854844-3 . P. 407.